The present invention relates to cosmetic compositions in the form of solid sticks such as sun care, moisturizing or analgesic sticks and antiperspirant/ deodorant sticks. These compositions have excellent efficacy as well as improved cosmetics.
There are three main types of such cosmetic formulations: compressed powder sticks, gel sticks, and wax sticks. While each of these formulation types may have advantages in certain use situations, each also has disadvantages. For example, compressed powder sticks are often brittle and hard, and leave a cosmetically-unacceptable dust upon application. Gels, while offering very good aesthetic characteristics, may be unstable due to interaction between the soap gelling agents typically used to solidify such sticks and the stick's "active" material (e.g., sunscreens and antiperspirant salts). Wax-based formulations can also yield cosmetically-unacceptable products due to such facts as hardness, greasiness, and stickiness.
Cosmetic sticks preferably glide easily over the skin surface, are not perceived as feeling gritty, and do not leave a visible residue. Soaps/alcohol gels can provide some of such cosmetic benefits. Examples of such soap gels are disclosed in U.S. Pat. No. 2,732,327, to Teller, issued Jan. 24, 1956; U.S. Pat. No. 2,857,315, to Teller, issued Oct. 21, 1958; U.S. Pat. No. 2,900,306, to Slater, issued Aug. 18, 1959; and U.S. Pat. No. 2,970,083, to Bell, issued Jan. 31, 1961. In addition, U.S. Pat. No. 4,382,742, to Marschner, issued Apr. 3, 1984 describes aqueous, transparent sticks containing bicarbonate in a propylene glycol/metal stearate gel. Wax based bicarbonate sticks containing silicones are described in U.S. Pat. No. 4,126,679, to Davy et al., issued Nov. 21, 1978. Emulsion sticks are also well known, having been disclosed, for example, in U.S. Pat. 4,122,029, to Gee et al., issued Oct. 24, 1978, and U.S. Pat. No. 4,265,878, to Keil, issued May 5, 1981.
While cosmetic sticks are old as evidenced by certain of the above patents, none of these publications suggests the criticality of the specific combination of components described by the present invention. This combination of components gives cosmetic sticks which are both highly efficacious and cosmetically pleasing.
It is therefore an object of the present invention to provide cosmetic sticks which have excellent cosmetic properties (e.g. ease of application to skin, "glide", and lack of visible residue) and are easy to manufacture. A further object of the present invention is to provide cosmetic sticks which very effectively deliver active materials to the skin, particularly sunscreen, analgesic, moisturizing, antiperspirant and deodorant actives. A still further object of the present invention is to provide cosmetic sticks with good high temperature stability. A still further object is to provide cosmetic sticks which impart a non-tacky, non-greasy cosmetically elegant feel to the skin.